Security attachment



FIG. 1 is a front view of a security attachment showing the claimed design;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof.

The broken lines in the figures show portions of the security attachment that form no part of the claimed design. 

CLAIM The ornamental design for a security attachment, as shown and described. 